← DoorDash Interview Insights

DoorDash·Software Engineer·Technical Phone Screen·Senior

Senior
Jun 2026

Summary

DoorDash data science interview with a product analytics case about diagnosing a drop in conversion rates on a food delivery platform. One question, pretty open-ended, felt more like a PM exercise than pure data science but apparently that's the vibe there.

Questions Asked (1)

Q1

Conversion rates on the food delivery app have been dropping for the past week. As the PM, how would you investigate what's causing it?

Root Cause AnalysisProduct Analytics & MetricsProduct Sense & Ideation
Author's notes

I spent way too long trying to be thorough and ended up just listing every possible thing that could go wrong.

Create a free account to read the full note

AI HintsAI Generated

Suggested Approach

Start by clarifying the metric definition and scope of the drop, then systematically segment the data to isolate the cause. Form hypotheses across the funnel, user segments, and external factors, and validate them with data and engineering investigation.

Pro tip: Always check for data instrumentation issues first—many 'metric drops' are actually logging or tracking bugs, especially if the drop is sudden and across all segments.

1. Clarify and Validate the Metric

Confirm what 'conversion rate' means (e.g., from app open to order placed), the exact time period, and whether the drop is real or a data anomaly. Check for instrumentation changes or logging errors.

2. Segment the Data

Break down conversion by dimensions like platform (iOS/Android), geography, user cohort (new vs. existing), restaurant category, and time of day to identify where the drop is concentrated.

3. Analyze the Funnel

Map the conversion funnel (e.g., app open → search → add to cart → checkout → order) and compare conversion rates at each step week-over-week to pinpoint where the drop occurs.

4. Form and Test Hypotheses

Generate hypotheses for the drop (e.g., recent app release, backend issues, pricing changes, competitor promotion) and validate them using data, A/B tests, or engineering logs.

5. Recommend and Monitor

Based on findings, propose immediate fixes or further investigations, and set up monitoring to track recovery and prevent future drops.

Key Points to Mention

  • Check for data instrumentation or logging errors before assuming a real user behavior change.
  • Segment by platform, geography, user type, and time to localize the issue.
  • Analyze the conversion funnel step-by-step to identify the exact drop-off point.
  • Consider recent app releases, backend changes, or third-party service outages.
  • Evaluate external factors like competitor promotions, seasonality, or weather.
  • Propose a hypothesis-driven approach and prioritize based on impact and likelihood.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.